Add a wrapper for open.

This centralizes the handling of O_BINARY and opens the way for hiding more
differences (like how open behaves with directories).

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@186447 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/tools/llvm-as/llvm-as.cpp b/tools/llvm-as/llvm-as.cpp
index d6f1919..b2e44ef 100644
--- a/tools/llvm-as/llvm-as.cpp
+++ b/tools/llvm-as/llvm-as.cpp
@@ -69,9 +69,8 @@
   }
 
   std::string ErrorInfo;
-  OwningPtr<tool_output_file> Out
-  (new tool_output_file(OutputFilename.c_str(), ErrorInfo,
-                        raw_fd_ostream::F_Binary));
+  OwningPtr<tool_output_file> Out(new tool_output_file(
+      OutputFilename.c_str(), ErrorInfo, sys::fs::F_Binary));
   if (!ErrorInfo.empty()) {
     errs() << ErrorInfo << '\n';
     exit(1);